Fosi Audio DS2 Portable DAC & Amp Review

[VintageFlanker]

Hello =)
Can I buy a cable from 4.4mm to 2 XLR (R + L) and use FOSI DS2 with active XLR studio monitors for example?

You absolutely can. Just be careful about software volume control.

 

[Esprit]

so now I find it quite confusing.

Which of these is the best?

 

[roladyzator]

The sound dropouts and fade-ins somehow got worse on my unit, so I wanted to send my DS2 for warranty, but got money back instead.
I went with FiiO KA15 and it's what I'd consider an end-game portable DAC/amp combo.

No dropouts, much less noticeable delay when starting music for the first time in Exclusive mode (no fade / delay at all if not using shared mode, of course).

One thing I'm not certain about is whether or not the 4.4mm jack is properly grounded for connecting via 4.4mm -> 2x XLR adapter to active speakers.
If it doesn't, this thing has an optical out through the 3.5mm jack, so I can use that to break ground loops should they appear.

 

[VintageFlanker]

(Europe) Master Deals Thread on Audio Product Sales

Thanks for testing Nicolas ... I've tried it from PC and even with a new mailadress from my mobilphone ... that's a bit spooky to me .. maybe they are testing the network/device id's (I have used their apps on both devices before ...) However, I've used the noted A7511AE8 and not the ASFR08...

www.audiosciencereview.com

 

[Robbo99999]

(Europe) Master Deals Thread on Audio Product Sales

Thanks for testing Nicolas ... I've tried it from PC and even with a new mailadress from my mobilphone ... that's a bit spooky to me .. maybe they are testing the network/device id's (I have used their apps on both devices before ...) However, I've used the noted A7511AE8 and not the ASFR08...

www.audiosciencereview.com

Nice & thanks, I just ordered this for £37 whereas is would be £63 on Amazon!

 

[Bl00dWolf]

Hello again =)
Question about iphone 16 pro and samsung s24 ultra with fosi ds2.
As we can see from the table, fosi displays the sampling rate with its LED.
I always have it red when connected to these smartphones. Is there any possibility to select sampling rate on them?

On the computer I can easily select it and the color of the LED changes.

I tried VOX, foobar2000, apple music player on iphone 16 pro, always red led, with M4A, FLAC tracks.
Same on adroid with aimp, foobar2000.

 

[staticV3]

View attachment 438911

Hello again =)
Question about iphone 16 pro and samsung s24 ultra with fosi ds2.
As we can see from the table, fosi displays the sampling rate with its LED.
I always have it red when connected to these smartphones. Is there any possibility to select sampling rate on them?

On the computer I can easily select it and the color of the LED changes.

I tried VOX, foobar2000, apple music player on iphone 16 pro, always red led, with M4A, FLAC tracks.
Same on adroid with aimp, foobar2000.

On Android, use USB Audio Player Pro, HiBy Music, Neutron Player, or FiiO Music.

All support direct access to USB DACs and bit-exact audio transmission, so audio won't be resampled by the Android OS.

 

[Bl00dWolf]

On Android, use USB Audio Player Pro, HiBy Music, Neutron Player, or FiiO Music.

All support direct access to USB DACs and bit-exact audio transmission, so audio won't be resampled by the Android OS.

I see you know a lot of things, your answers help me a lot. As in this case =)
Thank you very much!

Tried HiBy Music, set DSD Native, exclusive access to DAC.
Indeed, on DSD fosi ds2 led lit up blue, as indicated in the table.

Spoiler: photo

Hmmm, now I need to figure out same with iPhone 16Pro, which is my primary phone for everything =)

 

[masterhw]

Hmmm, now I need to figure out same with iPhone 16Pro, which is my primary phone for everything =)

I have same phone and a DS2. I find playing high sample rate content on Tidal is the only
time i’ve seen it change LED colour. I believe the app needs to implement a specific iOS API and sometimes it breaks, Tidal was just red for a couple months around December. but working now.

 

[Labjr]

I've found that FiiO Music app works with no issues on my Android phone. Install, scan for music files and go.

 

[Bl00dWolf]

I find playing high sample rate content on Tidal is the only
time i’ve seen it change LED colour.

I tried Flacbox on i16P and fosi ds2 led lit up yellow =) So it's working ok probably.
But no luck for native DSD =) Only PCM 384kHz max.

Neutron can play DSD as DSD native i think, but it's not free.

UPD: hiby also avalible on iOS

 

[Kuma]

If anyone’s interested, they were quick to help and they are sending me a replacement. Quick to reply to my email and quick to honor their warranty.

Received my replacement a couple of days ago. It’s working perfectly with the iPad and sounds great. Glad to have it back and happy that Fosi was quick to honor their warranty.

 

[knubbze]

I just bought one of these, and am also experiencing the fade-in at the start of tracks (standard PCM-based files such as FLACs, MP3s etc), together with audio drop-outs during playback on my Windows 10 (LTSC) machine. I've tried various USB ports and different cables, but the behaviour is still the same. I've tried it with my Android 14 phone and it exhibits none of these problems, which suggests that it's a configuration problem on my Windows machine. Has anyone managed to resolve these issues?

 

[Robbo99999]

My DS2 arrived today! I'm using it with an Android phone and Neutron Player to gain Direct Access to the DAC which bypasses any OS limitations. I think I've found the best way to use it in that configuration is to disallow Hardware Volume Control in Neutron Player which basically means that the volume buttons on the phone don't do anything even if you change the level and instead you control the volume of what you're listening to using the plus & minus buttons on the DAC itself. I think this way the music player is outputting the track at "0 dBFS" and then you're controlling the volume using the buttons on the DS2. (Well it's not outputting at "0 dBFS" because I'm using a -10dB negative preamp on my HE400se headphone EQ which is resulting in something like a 6dB bass boost of subbass and 4dB boost of the 1600Hz shouty region which is part of a Harman EQ for that headphone.).

Anyway, I've got a question on how the volume control buttons work on the DS2 in the situation I described in the previous paragraph. I've noticed that you can't keep the volume buttons held otherwise they don't change volume, you just have to keep pressing & releasing them to keep changing the volume one notch at a time. I worked out that you can't turn the volume off completely, you can't get to zero using those buttons as it will only get so quiet and then further pressing of the minus button has no effect. I then counted how many individual presses I raised the volume by to get to what I would describe as my normal listening level for the HE400se headphones and it was 45 presses of the volume increase button. Does anybody know how many increments of volume control is available through the buttons located on the DS2?

From what I understand I think I'm running the DS2 in the best possible way here? The idea being the music player is sending max possible digital signal to the DS2 and then the DS2 is "attenuating" the volume itself using the hardware volume control buttons on the DS2.

Listened with both my HD560s and HE400se and I enjoyed the HD560s session more, and I could have sworn the DS2 helped produce a better experience than what I'm normally used to vs either my desktop PC setup which is good measuring DAC (SoundblasterX G6) & JDS Labs Atom Amp, and also vs an Apple Dongle connected to my Android phone - but I'm kinda thinking it was just variability of the day and sometimes you're just more or less receptive to musical enjoyment, as I didn't do a direct comparison in the same session. Maybe just maybe the DS2 is doing something different that's audible, it certainly measures better than the Apple Dongle and would measure better or same vs my desktop setup, so maybe just maybe the DS2 is doing something different, but it's probably just random variation of my own brain!

(The DS2 didn't get even warm when being used for me.)

EDIT: answering my own question that I put in bold earlier in the post: apparently the DS2 has 60 step volume control according their website (at the link following this edit), but I'm a bit surprised at that given I was using it at 45th step out of 60, and given with European Apple Dongle (a weaker product) I don't recall running the volume that high relatively in terms of "number". Perhaps these different DACS have different "shapes" to their volume control curves.

Fosi Audio DS2 2024 New Mini Audio USB DAC Headphone Amplifier

A new generation USB-C portable headphone DAC and amplifier, supporting up to DSD256 and PCM 32bit/384kHz decoding for high-resolution sound reproduction. It delivers a powerful drive of up to 510mW@32Ω each channel, effortlessly powering high or low-impedance headphones with 3.5mm single-ended...

fosiaudio.com

 

[roladyzator]

My DS2 arrived today! I'm using it with an Android phone and Neutron Player to gain Direct Access to the DAC which bypasses any OS limitations. I think I've found the best way to use it in that configuration is to disallow Hardware Volume Control in Neutron Player which basically means that the volume buttons on the phone don't do anything even if you change the level and instead you control the volume of what you're listening to using the plus & minus buttons on the DAC itself. I think this way the music player is outputting the track at "0 dBFS" and then you're controlling the volume using the buttons on the DS2. (Well it's not outputting at "0 dBFS" because I'm using a -10dB negative preamp on my HE400se headphone EQ which is resulting in something like a 6dB bass boost of subbass and 4dB boost of the 1600Hz shouty region which is part of a Harman EQ for that headphone.).

Anyway, I've got a question on how the volume control buttons work on the DS2 in the situation I described in the previous paragraph. I've noticed that you can't keep the volume buttons held otherwise they don't change volume, you just have to keep pressing & releasing them to keep changing the volume one notch at a time. I worked out that you can't turn the volume off completely, you can't get to zero using those buttons as it will only get so quiet and then further pressing of the minus button has no effect. I then counted how many individual presses I raised the volume by to get to what I would describe as my normal listening level for the HE400se headphones and it was 45 presses of the volume increase button. Does anybody know how many increments of volume control is available through the buttons located on the DS2?

From what I understand I think I'm running the DS2 in the best possible way here? The idea being the music player is sending max possible digital signal to the DS2 and then the DS2 is "attenuating" the volume itself using the hardware volume control buttons on the DS2.

Listened with both my HD560s and HE400se and I enjoyed the HD560s session more, and I could have sworn the DS2 helped produce a better experience than what I'm normally used to vs either my desktop PC setup which is good measuring DAC (SoundblasterX G6) & JDS Labs Atom Amp, and also vs an Apple Dongle connected to my Android phone - but I'm kinda thinking it was just variability of the day and sometimes you're just more or less receptive to musical enjoyment, as I didn't do a direct comparison in the same session. Maybe just maybe the DS2 is doing something different that's audible, it certainly measures better than the Apple Dongle and would measure better or same vs my desktop setup, so maybe just maybe the DS2 is doing something different, but it's probably just random variation of my own brain!

(The DS2 didn't get even warm when being used for me.)

EDIT: answering my own question that I put in bold earlier in the post: apparently the DS2 has 60 step volume control according their website (at the link following this edit), but I'm a bit surprised at that given I was using it at 45th step out of 60, and given with European Apple Dongle (a weaker product) I don't recall running the volume that high relatively in terms of "number". Perhaps these different DACS have different "shapes" to their volume control curves.

Fosi Audio DS2 2024 New Mini Audio USB DAC Headphone Amplifier

A new generation USB-C portable headphone DAC and amplifier, supporting up to DSD256 and PCM 32bit/384kHz decoding for high-resolution sound reproduction. It delivers a powerful drive of up to 510mW@32Ω each channel, effortlessly powering high or low-impedance headphones with 3.5mm single-ended...

fosiaudio.com

Are you using the single-ended or balanced output with your HE400SE?
The single-ended output wouldn't be that much louder than a dongle, since it's just 2V instead of the usual 1V RMS.
It's 6 dB - a welcome, but not a huge jump.

I've had a DS2 (returned due to frequent sound dropouts and annoying volume fade-in after that) and now I have a Fiio KA15.
KA15 has similar specs (CS43198 DAC instead) and similar maximum output, and has a volume indicator on a LCD display (from 0 to 60).
I use HE400SE and have -6dB preamp gain for EQ.
Over the balanced output, I find 35-45 as a usable range (35-40 is OK, 40 to 45 a bit too loud for a longer session).
With the SE output, I have to use about 5-6 volume ticks more, which would indicate 1 click is 1 dB.

So, I think your experience is valid.

If you want to double-check if something isn't limiting your volume:
I've noticed that sometimes, the "Hardware volume" in UAPP that I use say that KA15 initializes into -15 dB.
The volume on the device doesn't change, so there is an extra volume control layer in the system.
Perhaps you could try enabling the hardware volume control in Neutron and max it out, see if changes anything.
Or you could check with a PC.

 

[Bl00dWolf]

Has anyone managed to resolve these issues?

Hello.
Try this https://www.audiosciencereview.com/...ttings-for-no-cutoff-delay.25838/#post-881748
or also you can try this

XMOS driver settings for no cutoff/delay

Es apsvēru iespēju izveidot sava veida "pamācību" visiem XMOS draiveriem ierīcēs, kurām ir nogrieznis — latentums starp skaņas sākumu un dac "reaģēšanu" un šīs skaņas atskaņošanu... Tātad šeit tas ir: XMOS draiveri izmanto vadības paneli, kas atšķiras no šī: Parasti izvēlnes "Opcijas", kas ir...

www.audiosciencereview.com

 

[Robbo99999]

Are you using the single-ended or balanced output with your HE400SE?
The single-ended output wouldn't be that much louder than a dongle, since it's just 2V instead of the usual 1V RMS.
It's 6 dB - a welcome, but not a huge jump.

I've had a DS2 (returned due to frequent sound dropouts and annoying volume fade-in after that) and now I have a Fiio KA15.
KA15 has similar specs (CS43198 DAC instead) and similar maximum output, and has a volume indicator on a LCD display (from 0 to 60).
I use HE400SE and have -6dB preamp gain for EQ.
Over the balanced output, I find 35-45 as a usable range (35-40 is OK, 40 to 45 a bit too loud for a longer session).
With the SE output, I have to use about 5-6 volume ticks more, which would indicate 1 click is 1 dB.

So, I think your experience is valid.

If you want to double-check if something isn't limiting your volume:
I've noticed that sometimes, the "Hardware volume" in UAPP that I use say that KA15 initializes into -15 dB.
The volume on the device doesn't change, so there is an extra volume control layer in the system.
Perhaps you could try enabling the hardware volume control in Neutron and max it out, see if changes anything.
Or you could check with a PC.

I've just been using the unbalanced output with my HE400SE. I'd need to get a balanced cable for it right if I wanted to use balanced? I don't need to use it though, so.

Yeah, we're probably in roughly the same listening levels.

Yep, I've tried Hardware Volume Control in Neutron Player and when the gain is maxed out using the volume buttons on the phone then it's the same loudness as when Hardware Volume Control is not activated in Neutron Player, so I worked out that not using Hardware Volume Control in Neutron Player automatically maxes out the signal sent from Neutron. I also didn't like it when Hardware Volume Control was activated because it meant that both the volume control buttons on the phone and also the volume control buttons on the DS2 could both change the volume together (independently of each other) so you would end up with a mish mash of volume combinations with both the phone and DS2 contributing the final loudness volume, so to me it made sense to turn off Hardware Volume Control and just use the volume control buttons on the DS2 as it's then more predictable where you are with it and I felt it was the best quality solution for the audio chain (but not entirely sure).

 

[Alter.Nate.37]

Hello,
I'm confused, the DS1 have on paper 120mW(SE); 220mW(BAL), the DS2 130mW(SE); 510mW(BAL).
But with these tests it results that the DS1 clips at 261 in 300 Ohm and 55 in 32, while for the DS2 it's 172 and 43?
Isn't that a huuuuuuuuuuuuuuuuuge discrepancy with the declared values?
Also, how is the test made? With which kind of device (virtual or real) and with which specs?
And do the 32 and 300 Ohm results refer to a balanced connection?

Thanks

 

[oleg87]

since Fosi’s specs don’t specify load impedance they’re basically meaningless.

 

[torgeirs]

Got my FOSI DS2
Great measurements. Some muting at samplerate change for windows, but OK for me,
Saw a neat noise thrick that I never saw before.
This is stepped 997 Hz measurments from -5dBFS input down to -50dB input.
From loud to quiet
L + R, R inverted out, by the way.

So at -50dBFS the noise goes down.
The other way round, from quiet to loud, the noise raises gradually from -25dBFS
dBr and dBFS

So its a hysteresis with the noise. If it is set by loud it will not reset from that value until less than -50dBFS is input for some (to me) unknown time.